This invention relates to a seat recliner mechanism and, more particularly, to a motor vehicle seat recliner mechanism which permits the seat back angle relative to the seat bottom to be varied in accordance with the desires of the motor vehicle occupant.
Many motor vehicles are now being provided, as standard or optional equipment, with seat recliner mechanisms which provide added comfort and convenience for the vehicle occupants. Numerous types of seat recliner mechanisms are known to the prior art. For example, U.S. Pat. No. 4,372,610, issued to A. J. Fisher, III et al on Feb. 8, 1983, describes a recliner employing a pair of meshing straight toothed racks. One of the racks is connected to the seat upper recliner structure through a quadrant component. Adjustment of the seat reclined angle is accomplished by changing the meshed position of one rack with respect to the other which is accomplished by operating an actuator. Although such devices perform satisfactorily, it is desirable to provide a seat recliner mechanism which is lighter in weight, less costly, and which provide smaller graduations between adjusted positions of seat back angle. It is further desirable to provide a seat recliner mechanism which provides a positive change in operating mode between engaged and disengagement thereby avoiding objectionable ratcheting as the recliner actuator is moved between positions. Additionally, it is necessary to securely fix the seat back position to prevent inadvertent changes in seat back position.
A seat recliner mechanism in accordance with this invention employs a curved toothed rack on a component which rotates with the upper recliner mechanism and which meshes with a gear that is rotatable within the lower recliner mechanism. Locking of the seat back is achieved by causing teeth of a pawl to engage the gear. Adjustments of seat back angle are provided when the toothed pawl is withdrawn from engagement with the gear, thereby permitting gear rotation as the upper recliner mechanism and the seat back rotate about their pivot point. The above design features are provided in accordance with the invention described by copending U.S. patent application Ser. No. 602,370, filed Apr. 20, 1984, which is assigned to the assignee of this invention and which is hereby incorporated by reference. This invention further discloses the addition of components which provides a quick release feature enabling the recliner locking mechanism to rapidly change from an engaged to a disengaged position.
The recliner mechanism according to this invention is usable for motor vehicle seats which are installed in two or four door type cars. In four door models, the front seat back does not need to be folded forward to permit access to the rear seat occupant area. However, in two door designs having a rear seat occupant area, such provisions are necessary. Therefore, this invention is described in conjunction with an inertia sensitive seat back locking device according to prior art designs which normally permit seat back folding but act to prevent folding when the vehicle is subjected to deceleration above a predetermined threshold level. The inertia sensitive seat back locking system shown in conjunction with this invention is also detailed by the previously mentioned issued U.S. patent.